When Ralph Fiennes was first approached about The Invisible Woman, he found it odd.
Not because of the story, about Charles Dickens' secret and much younger lover Ellen `Nelly' Ternan.
But the fact that he was so unaware, of both Dickens' work and of Nelly.
Fiennes, who directs and stars in The Invisible Woman, had actually only read one of Dickens' books before he started work on the film.
"I wasn't (familiar with Dickens), weirdly," he says, during a promotional trip to Sydney.
"And I still find it odd when I say it. I didn't have to read Dickens at school. I read lots of other stuff, but not Dickens."
And when it came to Nelly, who first became known to the world through Claire Tomalin's acclaimed 1990 biography, like many, Fiennes had no idea she existed.
"Yet it's well documented," he says.
"The book on which this film was based was published about 20 years ago, and it was successfully received, it wasn't as if it was under he radar. But it's funny how the iconic status of Dickens the storyteller, hasn't been permeated by this story of his pursuit of Nelly and the break-up of his marriage."
Fiennes was immediately intrigued by Nelly's tale. She was 18 and an actress when she first caught the eye of Dickens, at the height of his fame, and would eventually become his secret mistress until the English writer's death.
Initially, Fiennes didn't want to play Dickens. He had already directed and starred in a film - his directorial debut Coriolanus - and did not want to deal with the stress.
"It's just very hard for all the obvious reasons, you've got to put your head in two places," he says.
"(But) when this came along, it was benignly frustrating in that I could see the attraction of a role."
Fiennes started working on the screenplay with writer Abi Morgan (The Iron Lady) and would rehearse all the parts with her in the kitchen. He offered the part to another actor, who turned it down and in the end, Fiennes just couldn't say no.
"I said to the director, `Please, please consider me for Dickens'," he joked.
"They said, `I don't know. I don't know if you're right'."
Fiennes went from knowing hardly anything about Dickens, to immersing himself in the writers' life. What he discovered, was a man who was a "forcefield of energy" and a "powerhouse of creativity".
"The sort of man who walks into a room and it lights up," Fiennes says.
And The Invisible Woman, which centres on the story of Nelly (played by Felicity Jones), touches upon a very interesting part of Dickens' life.
"This part of his life which deals with the love affair with Nelly, we see a side of Dickens which is maybe hard to like - a controlling man, leaving his wife for a young girl," he says.
"He didn't do it well by anybody's standards I suppose, but I do feel he was a man who was frustrated in his marriage and just met Nelly and just had to go, just had to get out."
"One of his daughters is credited as saying, `My father is not a good man, but he was a great man'."
* The Invisible Woman is released in Australian cinemas on April 17